Actuating apparatus responsive to change in liquid level



Nov. 25, 1952 c, MAHONEY 2,619,566

ACTUATING APPARATUS RESPONSIVE TO CHANGE IN LIQUID LEVEL Filed Aug. 25, 1949 T1 .1. ea 20 a2 54 :1

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ATTORNEYS Patented Nov. 25, 1952 ACTUATING APPARATUS RESPONSIVE TO CHANGE IN LIQUID LEVEL Charles F. Mahoney, Baldwin, N. Y.

Application August 25, 1949, Serial No. 112,219

2 Claims.

This invention relates to apparatus adapted to be actuated in response to a change in liquid level, to mechanically move a related element to give notice of the change, as by causing a visual or audible signal, or by causing a source of heat for a boiler to be turned on or off, or by actuating controls to cause a lowering water level to be raised or a rising water level to be lowered etc.

An object of the invention is to provide a simple, practical and durable apparatus of the above mentioned kind.

Another object of the invention is :to provide apparatus of the above mentioned kind which will react promptly to a change in water level.

Another object of the invention is to provide apparatus of the kind described which will be easy to make and to install and maintain.

Other objects of the invention will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, arrangement of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as will be pointed out in the following description, and the scope of the application of which will be indicated in the following claims.

The invention will best be understood if the following description is read in connection with the drawings, in which,

Figure l is a view partly in cross section and partly schematic showing an apparatus embodying the invention applied to the boiler of a furnace; and

Figure 2 is a detail view showing the apparatus and part of the furnace wall in cross section.

In the embodiment of the apparatus as shown herein my apparatus comprises a control box H) from the rear end of which protrudes the hollow metallic finger I2. The inner end of the finger is open and communicates with a port I4 in the inner face of control box It, but the outer end [6 of finger I2 is closed.

Finger 12 comprises the portions !2 and I2, the latter portion being of reduced diameter. On portion l2 adjacent its inner end the screw threads it are provided by which the device is firmly engaged within the bore 20 extending through furnace wall 22, the bore being grooved to receive the threads 13. Preferably finger I2 is made long enough so that its inner end will protrude into the fluid container or boiler in connection with which it is employed, and control box ID will be spaced outwardly from the outer surface of the furnace wall a substantial distance, to reduce the effect on the controls in box In of radiant heat from the furnace wall, making the controls substantially dependent upon heat transmitted to the control box by conduction through strip 24.

Strip 24 is a heat conductive metal strip which may be of bimetal, or of a thermostat metal which is available on the market under the trade name Truflex. It will be noted that strip 24 comprises an inner portion 24*, an intermediate re- "versely curved portion 24 and an outer portion 24. Portion 26 is disposed along, and in abutting-relation to, the inner surface of finger l2, and being highly heat sensitive and conductive it readily conducts to its inner portion 24 heat transmitted to its portion 24 by contact with finger I2.

Positioned within finger I2 adjacent its closed inner end 16 is a heating unit 26 which may be energized from any suitable source as for example by the conductors 28 and 30 which may lead to any convenient source of electric energy such for example as the house supply.

By means of heating element 26 the metal shell comprising finger I2 is continuously supplied with heat, but so long as fluid, such for example as the water of a furnace boiler is in contact with the shell of finger l2 a substantial portion of the heat thus transmitted from heating element 26 is transferred to the water. However, when the liquid level falls so that it is no longer in contact with finger [2 the temperature of the metal shell rises quickly under the influence of heating element 26 with the result that sufiicient heat is transferred to portion 24 of strip 24 to cause portion 24 to be heated to above a critical temperature thereby causing the strip to bend and in so doing to actuate some associated e ement or instrumentality such for example as the switch bar 32 shown in Figure 1, or the microswitch indicated generally by the numeral 34 in Figure 2.

The instrumentalities which may thus be actuated by movement of strip 24 are many and varied and will not be described in detail since they form no part of the present invention. As an illustration of one such instrumentality there is shown in Figure l in connection with movable switch bar 32 a circuit through said switch bar, contact 35, lead 38, white lamp 40, lead 42 to lead 44 and back t switch bar 32, which is closed when strip l2 has not been heated above its critical point and thus is not moved to contact switch bar 32. When, however, strip 12 is heated above its critical point and moves against switch bar 32 thus causing it to move against contact 46, a circuit is c osed through lead 48, the red lamp 58, and lead 52 to lead 44 and back to the switch bar 32. As shown in Figure 1 when switch bar 32 is moved against contact 46 it is also moved against contact 54 and closes a circuit through leads 56 and 44 interconnecting switch bar 32 and contact 54 with a heat source control, such for example as the control ofan oil burner -unit indicated generally by the numeral 58.

In Figure 2 the instrumentality which is actuated by movement of strip .24 is illustrated as micro-switch 34 from which leads are :shown running to a control means which is not identified.

It will be understood that coolingof the-metal shell comprising finger l2, as by the rising of liquid into contact with the shell willalso-cause movement of portion 24 of the strip 24 when the contact of the liquidwith the sheH-cauSesa-heat change "in portion 2 1 of the :strip sufiicient -to .cause a contraction and-movement of. strip :24 opposite-to that-causedby heating of said strip.

-My"actuating apparatus has the advantagesof simplicity and durability coupled with positive vquiclrresponse.

. It :will. thus be seen that there has been providedby this invention an apparatus in which the various objects hereinabove :set forth together with many thoroughly practical advantages are successfully achieved. "As various ,possibleembodiments-might :bemade of themechan-ical features ,of the above, invention-and .as therartL-herein :described might bevariedinvarious ,parts,:-a1l without departing from the scope of the ,invenextending through the boiler --wall with a portion thereof outside the "boiler and a portion :thereof inside the-boiler, a heat-conductive strip largely contained within ,said envelope'and ex- ;posedsubstantially along-the median line of said envelope and includes the endwhich projects beyond said envelope, the second portion of said strip being disposed parallel with and in contact with said envelope, to receive heat directly from said envelope, ;a source of heat within said envelope theefiect of which on said envelope is normally offset bythe fluid in said boiler but which serves to heat said envelope sufficiently to cause said envelope to transmit suificient heat to said strip to cause movement of the projecting end of said strip when the fluid level in said boiler changes so asto' be. out of I contact .with said envelope.

'2. AloW-water power. cut-01f for a boiler comprising arbimetal strip, azhousing for the strip :adaptedito-extend through the .wall of a boiler, a

:sourceof heat withinisaid housing-the effect of :whichronisaid housingiis normally ofiset by the fluid .in:said:boiler,;said bimetalistrip having a portion :parallel ito, and in contact with .said housing within said housing, and a portion extendingbeyondsaid housingoutside of'said boiler and :adapted 'to .bend :when the temperature in the housing rises above a predetermined range due to beingnncovered: by wateriinthe boiler, and an :electrical Jcircuit including :a :switch :positioned toiberactuatedrwhen saidrbimetal strip bends.

CHARLES F. MAHONEY.

vREEERENCES "CITED The following references-are of record in the file ofthis patent:

UNITED. STATES .PATENTS :Number Name Date 2,063,705 :Smulski Dec. '8, 1936 2,165,569 Obemaier July 11,1989 2,304,211 :Sparrow. Dec. 8, '1942 2,468,676 ,=Liben ,-Apr. 26,1949 

